US2892796A - Detergent composition containing phosphated alkyl glyceryl ether corrosion and tarnish inhibitor - Google Patents

Description

June 30, 1959 H. w. MCCUNE 2,892,796

DETERGENT COMPOSITION CONTAINING PHOSPHATED ALKYL GLYCERYL EITHER CORROSION AND TARNISH INHIBITOR Filed Oct. 5, 1956 Way/2f 1055 2 29.

IN VENTOR BY wmmGR- ;CMJ{ L was,

ATTORNEYS DETERGENT COMPOSITION CONTAINING PHOS- PHATED ALKYL GLYCERYL ETHER CORRO- SION AND TARNISH INHIBITOR .Homer W. McCnne, Wyoming, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio Application October 5, 1956, Serial No. 614,186

8 Claims. (Cl. 252-137) The present invention relates to heavily built synthetic detergents and specifically to a novel compound for preventing the builders in such detergents from attacking metals.

It is an object of this invention to provide a heavy duty (heavily built) detergent composition, protected against corroding aluminum and zinc and against the tarnishing of copper alloys such as German silver.

Heavy duty synthetic detergents of the prior art have been inhibited from corroding aluminum and partly inhibited from corroding zinc by silicate of soda and from tarnishing German silver by such tarnish inhibitors as ethylene thiourea and benzotriazole. Silicate of soda has the disadvantage that the carbon dioxide of the air reacts with the Na O of the silicate, thus forming insoluble .silicates.

When a detergent containing these insoluble silicates is poured into water, the finely divided portion floats on the surface of the water as a floc. The coarser portion sinks to the bottom and appears to be sand. These phe: nomena lead the housewife to believe the detergent is adulterated with a sandy material.

The fact that an additional additive to inhibit the tarnishing of German silver is required, is an item of expense.

Some calcium sequestrants, if not inhibited, will corrode aluminum and zinc, and tarnish coppery alloys like German silver. I have discovered that a certain class of preparations will inhibit these effects. These preparations are phosphated alkyl glyceryl ethers wherein the alkyl groups are from 14 carbons to 18 carbons inclusive in chain length. The phosphation may be carried out with from 1 to 3 atoms of phosphorus from a phosphating agent, per mole of alkyl glyceryl ether. The phosphated alkyl glyceryl ether is useful in amounts from about /2% to about 20% of the calcium sequestrant. It is effective above 20% but no additional protection is achieved.

The corrosion of aluminum by alkalis is well known, but the corrosion by sequestrants is almost unrecognized. Sequestrants corrode aluminum much worse than nonsequestering alkaline materials even at the same pH. The instant invention contemplates the reduction of corrosion by sequestrants whether these are used as such, ,or whether they are employed as builders in synthetic detergent compositions.

The corrosive calcium sequestrants against which the phosphated alkyl glyceryl ether is effective are the water soluble salts of tripolyphosphoric acid, ethylene diamine tetra acetic acid, hydroxy ethyl ethylene diamine triacetic acid, and nitro triacetic acid. The amino polycarboxylic compounds containing at least 3 acetate radicals are normally used in the form of their sodium salts as are the tripolyphosphates.

The starting compound for the alkyl glyceryl ether phosphate of the present invention is alkyl chloroglyceryl ether, prepared by reacting epichlorohydrin with a fatty alcohol. The chlorine is hydrolyzed oif of the compound, producing principally- H In practice, not all of the chlorine is removed. Up to about-25% of the hydrolyzed material may be present as chloroether.

The hydrolyzed chloroether is then reacted with POCl or other phosphating agents later described and the reaction product neutralized with sodium hydroxide or other suitable alkali.

The preparations of the alkyl g'lyceryl ether phosphate is carried out as follows.

EXAMPLE I Hydrolysis.-68.7 grams of alkyl (tallow) glyceryl ether chloride made by condensing 1 mole of alcohols derived from tallow with 14 moles of epichlorohydrin were refluxed in 3.44 liters of 50% dioxane50% water containing 172 grams of sodium bicarbonate for 18 hours. 213 milliliters of concentrated sulfuric acid were added and the refluxing continued for 27 hours. The solution was extracted with petroleum ether and the dissolved solid recovered by evaporation. The solid recrystallized from hot alcohol-water was obtained in a yield of 60.9 grams or 94% on a basis of ROCH CHOHCH OH.

Phosphation..88.9 grams of alkly glyceryl ether prepared as shown above was dissolved in 250 milliliters of ethylene dichloride. Some solvent was distilled ofi to remove water. The contents of the flask were covered with nitrogen. 81.4 grams of POC1 and 1.03 milliliters of PCl were added and the mixture heated one-half hour. 19.1 milliliters of water were added and the resulting HCl was removed by nitrogen sweeping and the slow (4 hours) distillation of solvent. The product was dried under an infra-red lamp. A yield of 113 grams was obtained.

Neutralization of the acid.-The product from the above was dissolved in 186 milliliters of 2 normal aqueous NaOH annd then salted out with 1600 milliliters of ethyl alcohol. A yield of 32 grams was obtained.

The product contained 8.24% of combined phosphorus. If the phosphation has formed a phosphate ester at each of the two hydroxyls of the alkyl glyceryl ether the phosphate content would have been 10.6. This deficiency of phosphorus may in part be explained by the fact that the chlorine content was 1.29% indicating that not all of the terminal chlorine atoms were bydrolyzed off the chloroether.

Standard corrosion test-The aluminum strips were cut from The Aluminum Company of America 35 grade aluminum. This contains about 1.2% manganese. The strips were 3 inches long, inch wide and 0.041 inch thick. They were polished with steel wool, followed by wet pumice, and then washed with water and alcohol. After air drying they were weighed on an analytical balance. They were immersed in 200 milliliters of test solution in a 250 ml. Erlenmeyer flask. The strips were leaning at an angle to the bottom of the flask of about 40. The flasks were held at F. for three hours, unless otherwise noted. After the tests the strips were removed, washed in water and immersed in concentrated nitric acid for 3 minutes to remove products of corrosion. They were then washed in water and alcohol, air dried and weighed again.

The breadth of protection afforded to a variety of non-ferrous metals by the phosphated alkyl .glyceryl ether is shown by the following tests, made with the above phosphated alkyl glyceryl ether which is abbreviated to PAG in the table, and with similar solutions, described below, containing no phosphated alkyl glyceryl ether I and listed under the heading No inhib.

specific gravity, that is, simply reporting loss of weight in milligrams, had to be modified. These results are v therefore reported as weight loss in milligrams per square centimeter of surface per hour. This is abbreviated in the table to mg./crn. /hr.

Tarm'sh and corrosion of various metals Wt. Loss, mgJcmfl/hr. Appearance of Metals Strips with 0.02 FAG No 0.02% Inhib. PAG

Aluminum 3S 0.221 0.006 Stain replaced by whitened appearance. A zinc alloy containing' 4% alum- 0.102 0.005 No tarnish.

lnum. 0.04% magnesium, the remainder being zinc. A zinc alloy containing 4% alum- 0. 090 0.000 Do.

inum, 0.04% magnesium, 1% copper, the reaminder being zinc.

Brass, Admirality (70% Cu, 29% 0.009 0.000 Purple coloration Zn. 1% Sn). prevented. Copper 0.003 0. 000 Darkening prevented. Cadmium 0.054 O. 000 Spotty dulling prevented. Zinc 0.062 0. 024 Slight stain prevented. Base metal from a. household 0. 090 0.005 Stain prevented. washing machine. German silver alloy 15 (15.5% Ni, 0.007 0. 000 Slight discoloraf 18.8% Zn, 63.7% Cu). tion.

gr. H 0, 3 hrs., 60", pH 9.5

These tests show that compositions containing sodium triphosphate will be protected against corrosion of many of the metals used in washing machines and the tarnishing of coppery alloys by phosphated alkyl glyceryl ether.

7 EXAMPLE II 5.1 grams of P0Cl were dissolved in 100 ml. of ethylene dichloride in a flask. Nitrogen was bubbled through 30 minutes with nitrogen sweeping continued. The solvent was removed by distillation, the residue dissolved in water and neutralized to a pH of about 10. This solution of alkyl glyceryl ether phosphate was as effective in preventing corrosion and discoloration as the preparation of Example I.

EXAMPLE III The alkyl glyceryl ethers may be phosphated with P 0 polyphosphoric acid and orthophosphoric acid; even 85% orthophosphoric is elfective in phosphating the alkyl glyceryl ethers as will be shown below. The P 0 tended to produce a product of only moderate activity as a corrosion inhibitor, and the 85% orthophos phoric required 40 hours of heating to produce an eifective corrosion inhibitor, but the phosphated alkyl glyceryl ethers seem to be effective no matter how they are phosphated, as indicated by the following tests.

The phosphating agent and the tallow glyceryl ether were mixed in a glass tube fitted with a stirrer and con- 1 'nected to a water aspiraton The stirring shaft was fitted with a. number of prongs to make the stirring more etficient. The mixtures were stirred under water aspirator vacuum (about 15 mm. abs. pressure) for the times and at the temperatures shown in the table below. The compounds in the acid state were added to the test solutions, where they were immediately neutralized by the alkalinity of the test solution.

The preparations were used in the standard corrosion test previously described. The aqueous solution con tained 0.18% of sodium tripolyphosphate, 0.06% of the sodium salt of keryl benzene sulfonate and 0.02% of the phosphated alkyl glyceryl ether. This is the concentration that would be achieved if an 0.03% solution were prepared from a detergent of the following composition:

Parts by wt. Sodium tripolyphosphate 60 Sodium salt of alkyl benzene sulfonate 20 Phosphated tallow glyceryl ether 6.7

Water and inert salts 13.3

The hardness of the water used was 7 grains CaCO equivalent per gallon and the tests were run at 60" C. The results of the corrosion test follow.

Average corrosion without the inhibiting phosphated glyceryl ether but with other constituents present was 14.0 mgs.

It should be noted that the acid phosphate as prepared or the neutralized product used in Example I, may be used. The optimum amount of phosphating agent is that which furnishes two atoms of phosphorus per mole of alkyl glyceryl ether.

Preparations have been made with the ratio of phosphating agent to alkyl glyceryl ether as low as 1 atom of phosphorus (as P 0 or P001 These low ratio preparations have inhibiting eifects but their effectiveness is not as great as those prepared with about two atoms of phosphorus in P 0 or POCl per mole of glyceryl ether.

EXAMPLE IV The eifect of most anionic detergents is slight on the inhibiting effect of phosphated glyceryl ether in water of varying hardness. The following test shows the weight loss in milligrams, in the standard test with 0.18% sodium tripolyphosphate, 0.06% anionic, 0.02% phosphated alkyl glyceryl ether.

Hardness, gr./gal. as CaOO; 0 7 14 21 grain grains grains grains Anionic Detergents (Sodium Salts):

Keryl Benzene Sulfonate .5 1.4 1. 5 5. 4 Dodecyl Sulfate 9 2. Q 4. 8 3. 2 Dodecyl glyceryl ether sulfonate. 1.1 4. 3 4. 8 3. 4

I of the sodium tripolyphosphate was replaced by sodium ethylene diamine tetra acetate, the Weight loss in the standardcorrosion test was reduced from 3.4 mg. to 0.8 mg. Since nitrilo triacetate and the sodium salt of hydroxyethyl ethylene diamine triacetic acid reduce precipitation of alkyl glyceryl ether, the latter is more effective' in inhibiting corrosion in hard water when either of these sequestrants is used than when the sequestrant is tripolyphosphate.

The figure shows the range over which the phosphate'd alkyl glyceryl ether is effective as a corrosion inhibitor. These tests-were made under the conditions described hereinbefore under the heading Standard Corrosion Test with an 0.18% concentration by weight of sodium tripolyphosphate, an 0.06% concentration of sodium tetra propylene benzene sulfonate, in 7 grain (calculated as CaCO water. The pH was 9.5. At .0018% concentration, which is 1% of the sodium tripolyphosphate concentration, the weight loss from corrosion is only about 9 milligrams as compared with a loss of 14 milligrams in the absence of inhibiting agent. The curve is about flattened out at 0.030% but it is obvious that up to 20% of the sodium tripolyphosphate concentration (20% of 0.l8%).036% would be useful. While this test was made at a pH of 9.5, tests conducted at other pHs show that the phosphated alkyl glyceryl ethers are effective at a wide range of pH values.

While the alkyl glyceryl ether phosphates are not eifective to inhibit corrosion when used in amounts less than 1% by weight of thesodium tripolyphosphate, they are effective as a tarnish inhibitor for German silver in lesser amounts. When tested in the following formula the tarnishing of German silver was no more noticeable than when 0.02% benzotriazole was substituted for the alkyl glyceryl ether phosphate in the same formula.

EXAMPLE V 50.0 parts by weight sodium tripolyphosphate 17.5 parts by weight anionic detergent (about equal proportions of sodium alkyl sulfate wherein the alkyl is about 65% dodecyl radicals, the remainder being decyl and tetradecyl; and sodium polypropylene benzene sulfonate wherein the polypropylene averages about 12 carbon atoms 15. parts by weight sodium sulfate 6.0 parts by weight sodium silicate 11.3 parts by weight water and miscellaneous .25 part 'by weight alkyl (tallow) glyceryl ether phosphate Since the benzotriazole as described in US. Letters Patents 2,618,606 and 2,618,608 is one of the most effec tive tarnish inhibitors used with sodium tripolyphosphate,

this example shows that the alkyl glyceryl ether phosphate will be effective in amounts as small as 0.5% of the sodium tripolyphosphate. The type of synthetic detergent that is present with the calcium sequestrant has only a moderate effect on the inhibiting effect of the alkyl glyceryl ether phosphate.

EXAMPLE VI Detergent: Loss in weight, Milligrams Sterox CD 5.1 Pluronic F68 8.2

Sterox CD made by Monsanto is a tall oilxethylene oxide condensate about nine moles of ethylene oxide being condensed with one mole of tall oil. Pluronic F68 (Wyandotte) is a condensate of ethylene oxide with a hydrophobic base formed by condensing propylene oxide With propylene glycol. The molecular weight is about Referring to the anionics and nonionics which can be compounded with calcium sequestrants and be improved by the addition of alkyl glyceryl ether phosphate, the anionics may be denoted by the formula RXMA where R is the hydrophobe, usually from 10 to 20 carbons,-and may be (1) fatty acid including acid chloride, (2) alcohol, and (3) alkylaryl; X is the linkage, which may be (1) direct, (2) ester, (3) ether, (4) amide, (5) polyethenoxy (at least ten different types), and (6) multiple; M is the hydrophilic group, which may be a (l) sulfate, (2) sulfonate and (3) phosphate; and A is the alkali group including (1) sodium, (2) potassium, (3) lithium, (4) ammonia, (5) substituted ammonia, (6) magnesium, and (7) calcium.

It may be readily perceived that the number of anionics is quite large. With ten different hydrophobes and at least ten polyethenoxy linkages, which would make the number of linkages 15, the number of anionics becomes R X M 30 15 13:1350

without considering the alkaline group, which multiplies 1350 by 7 to equal 9450.

This over-simplifies the situation, as there are a great many variations possible, such as secondary and tertiary alcohols, several alkylaryl radicals etc. It will be perceived that it is impossible to list all of the anionics with which calcium sequestrants and alkyl glyceryl ether phosphate may be used.

The corrosive action of calcium sequestrants, when used with the following typical anionics, is effectively reduced by alkyl glyceryl ether phosphate:

oleylmethyl The nonionic synthetic detergents have a hydrophobe similar to the hydrophobe in the anionics, but somewhat more diverse in structure and have an active carboxyl or hydroxyl group. The hydrophobe is usually linked directly to the hydrophilic group although a linkage group is present in some nonionics. The hydrophilic group is usually ethylene ether containing 5 to 30 ethylene oxide radicals although propylene oxide and mixtures of ethylene oxide and a propylene oxide may be used.

The ethylene oxide will react with hydroxyl on the hydrophobe to form an ether linkage or with a carboxyl on the hydrophobe to form an ester linkage. With a wide variety of compounds ending in carboxyl or bydroxyl groups and with polyalkylene oxide groups containing from 5 to 30 moles, it will be perceived that the number of nonionic synthetic detergents is quite large.

The corrosive action of calcium sequestrants, when 'used with the following typical nonionics, is efiectively reduced by alkyl glyceryl ether phosphate:

Reaction products of 1 mole of oleyl alcohol and moles of ethylene oxide.

, Reaction product of 1 mole ot dodecyl phenol' and .6

moles of ethylene oxide.

The oleic acid ester of sorbitol which has'been etherified with 2 moles of ethylene oxidepermole of sorbitol.

The reaction product of nine moles of ethylene oxide with 1 mole of dioc'tyl phenol. The Sterox CD and Pluronics F68 referred to in Example. VI. 1 L While the alkyl glyceryl ether phosphate will minimize the corrosion of aluminum by calcium sequestrants in the presence of anionic and nonionic' detergents, it is not l-useful in the presence of cationic detergents. The alkyl glyceryl ether phosphate itself is an anionic material and will thus combine with thecationic; to form. an insoluble, inactive compound.

The chemical formula for the phosphated alkyl glyceryl ether thatis the effective corrosion and tarnish inhibitor These can be made by high pressure hydrogenation, which saturates the double bonds of. the tallow as well as con- -verting the tallow to the alcohol. These may also be made by low pressure hydrogenation of the tallow, followed by sodium reduction to form the alcohol. Both are called hydrogenated. Preparations in which the'alkyl radical was .mainly the dodecyl'radical were not as effective as-those containing the l4,"16 and 18 carbon alkyl radical s'. .The phosphated'alk yl glyceryl ethers of this inventionshould contain alkyl radicals-of 14m 18 carbons, either singly or-in mixtures, and. any suchothers, or mixtures thereof, may be substituted in any of the 'foregoing specific examples with comparable results.

Since the hydrolyzed chloroether has the formula noomornorn it was at first believed that the diphosphate was'the active material. This. is- V None of my inhibiting compounds contain this much phosphorus noris the discrepancy completely explained by the presence of thechlorine which off of the molecule.

is not hydrolyzed Itis possible that steric hindrance keeps the phosphating agent from reacting with the secondary hydroxyl I group. One may also speculate that compounds of a cyclic'nature may be present-like this These are strictly theories and I do not wish to be bound by them. What is-known, is that the most active "compounds containsomewhat more than one atom of phosphorus per mole of alkyl glyceryl ether used, but the I exact composition of the reaction product is notyet known. v

Havingthus described my invention, what I claim is:

1. A detergent composition comprisinga calcium scquestrant selected from the group consisting of watersoluble salts of tripolyphosphoric acid, of ethylene diamine tetra acetic acid, of hydroxy ethyl ethylene diamine triacetic acid, of nitrilo triacetic acid, and mixtures there of, and the reaction product of an alkyl glyceryl ether, containing from14 to 18 carbon atomsin-thealkyl chain, with an amount of inorganic phosphating agent sufiicient to supply at least one gram-atomic weight of phosphorous per gram-molecular weightof alkyl glyceryl ether, the said reaction product being present in an amount from about /2% to about 20% by weight of the calcium seqnestrant, the said detergentcomposition being inhibited from tarnishing coppery alloys and corroding aluminum and zinc by the said reaction product; a i

2. The detergent composition of claim .1 wherein the alkyl group of the alkyl glyceryl ether is derived from hydrogenated tallow. 1 I

3; The detergent composition of claim 1 wherein the calcium sequestrant is sodium tripolyphosphate.

4. The detergent composition of claim 1 wherein the tarnish and corrosion inhibiting agent is the reaction product of the alkyl glyceryl ether with an amount of phosphating agent sufficient to supply two gram-atomic weights of phosphorous per gram-molecular weight of ether, and the said reaction product contains about 8% phosphorous by weight. 1 l a 7 5. The detergent composition of claim 4 wherein the phosphating agent is phosphorous 'oxychloride and is present in the amount of two 'mole's per mole of the alkyl glyceryl ether.

6. The detergent composition of claim '5 .wherein the tarnish and corrosion inhibiting agent is the neutralized reaction product of the alkyl glyceryl ether and the phosphating agent.

7. A detergent composition inhibited'frorn tarnishing coppery alloys and from corroding aluminum and zinc which comprises a calcium sequestrant selected from the group consisting of the water-soluble salts of tripolyphosphoric acid, of ethylene diamine tetra acetic acid, of hydroxy ethyl ethylene diamine triacetic acid, of nitrilo triacetic acid, and mixtures thereof, anon soap' anionic organic synthetic detergent, and -'the 'reactionproduct of an alkyl glyceryl ether, contai fil glfrom 14 "to'1 8 carbon atoms in the alkyl chain, with'an amount of inorganic phosphating agent sufiicient to supply atleast one gramatomic weight of phosphorous per gram-molecular weight of alkyl glyceryl ether, the said reaction product being present in an amount from about%% to about 20% by weight of the calcium sequestrant.

8. A detergent composition inhibited from tarnishing coppery alloys and from corroding aluminum and zinc which comprises a calcium sequestrant selected from the group consisting of the water-soluble salts of tripolyphosphoric acid,.of ethylene diamine tetra acetic acid, of hydroxy ethyl ethylene diamine triacetic acid, of nitrilo triacetic acid, and mixtures thereof, a non-soap nonionic organic syntheticjdetergent, and the reaction product of an alkyl glyceryl ether, containing from 14 to 18 carbon atoms in the alkyl chain, with an'amount of inorganic phosphating agent sufficient to supply at least one gramatomic weight of phosphorous per gram-molecular weight of alkyl glyceryl ether, the said reaction product being present in an amount from about V2% to about 20% by weight of the calcium sequestrant.

References Cited in the file of this patent UNITED STATES PATENTS 2,224,695 Prutton Dec. 10, 1940 2,618,603 Schaetfer Nov. 18, 1952. I 2,744,128 Morris 'May 1, 1956

Claims (1)

1. A DETERGENT COMPOSITION COMPRISING A CALCIUM SEQUESTRANT SELECTED FROM THE GROUP CONSISTING OF WATERSOLIBLE SALTS OF TRIPOLYPHOSPHORIC ACID, OF ETHYLENE DIAMINE TETRA ACETIC ACID, OF HYDROXY ETHYL ETHYLENE DIAMINE TRIACETIC ACID, OF NITRILO TRIACETIC ACID, AND MIXTURES THEREOF, AND THE REACTION PRODUCT OF AN ALKYL GLYCERYL ETHER, CONTAINING FROM 14 TO 18 CARBON ATOMS IN THE ALKYL CHAIN WITH AN AMOUNT OF INORGANIC PHOSPHATING AGENT SUFFICIENT TO SUPPLY AT LEAST ONE GROM-ATOMIC WEIGHT OF PHOSPHOROUS PER GRAM-MOLECULAR WEIGHT OF ALKYL GLYCERYL ETHER, THE SAID REACTION PRODUCT BEING PRESENT IN AN AMOUNT FROM ABOUT 1/2% TO ABOUT 20% BY WEIGHT OF THE CALCIUM SEQUESTRANT, THE SAID DETERGENT COMPOSITION BEING INHIBITED FROM TARNISHING COPPERY ALLOYS AND CORRODING ALUMINUM AND ZINC BY THE SAID REACTION PRODUCT.

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